In various surgical procedures fasteners in the form of staples, and the like, are employed for holding tissue portions together to facilitate healing of a wound or incision. For example, a locking staple having a tongue and groove structure by which the staple is locked, is disclosed in U.S. Pat. No. 2,881,762. A metal staple, especially adapted for ligating blood vessels, is disclosed in U.S. Pat. No. 3,079,608. International Patent Application No. PCT/SU79/00049 discloses a variety of fastening devices and instruments for performing circular anastomosis on the large intestine. The aforementioned disclosures serve as examples for a wide variety of tissue fastening devices and techniques that may be employed in general and/or specific surgical situations.
One common type of fastening device for joining or holding together soft tissue portions is the generally U-shaped staple which is typically fabricated from suitable metals. Such staples, although generally described as having two legs joined by a link to define a U-shape when unclinched, may also be regarded as having a configuration of an open loop when unclinched. The legs need not be necessarily parallel but are typically adapted for penetrating the tissue portions and for receiving between them some of the tissue material.
Other examples of U-shaped or open loop staples as well as methods and instruments for applying said staples to tissue are disclosed in U.S. Pat. Nos. 3,252,643, 3,482,428, 3,692,224, 3,790,057, 3,795,034, 3,889,683, 4,198,982, 4,316,468 and 4,329,576.
Other tissue fastening devices have been proposed and differ from staples per se in that these other devices may have a plurality of components that do not have to be clinched in the manner of a metal staple. One such device is disclosed in U.S. Pat. No. 4,060,089 and includes a fastener strip provided with a plurality of longitudinally spaced parallel prongs which are adapted to penetrate overlapped tissue portions from one side so that the distal ends of the prongs project from the other side of the tissue portions.
The fastener device further includes a retainer strip which is adapted to be placed on the other side of the tissue portions opposite the fastener strip to engage the ends of the projecting fastener strip prongs and to secure the tissue portions tightly between the fastener strip and the retainer strip. The fastener strip prongs each include a plurality of spaced apart engaging members for engaging the retainer strip at the desired position relative to the prongs. This provides for the capability of adjusting the distance between the fastener strip and the retainer strip. Such a fastening device may be fabricated from a bio-degradable or absorbable material.
Other patents such as U.S. Pat. Nos. 2,286,578 and 3,638,654 disclose instruments for applying flexible sutures with needles that are inserted into the tissue portions.
Other types of fasteners that include a fastening member with legs joined by a link and secured by a retaining receiver on one side of an incision are disclosed in U.S. Patent Application Ser. Nos. 506,088; 506,151; and 506,083 filed June 20, 1983 and assigned to the assignee of the instant application.
U.S. Pat. No. 4,006,747 discloses the application of a flexible fastener to tissue by means of a slotted hollow straight needle with a plunger for pushing the fastener through the needle. The application of a similar fastener in a non-surgical situation is disclosed in U.S. Pat. No. 4,215,807.
Also, in commonly assigned patent application Ser. No. 506,146 filed June 20, 1983 an instrument having a pair of spaced apart needles oriented in generally parallel planes is disclosed. Each needle has a distal end adapted for piercing the tissue portions. Each needle is hollow and has a passage extending along its length from a fastening member receiving opening to a discharge opening at the distal end of the needle. Each needle also has a slot extending along its length in communication with the passage and facing the slot of the other needle. According to the method of that patent application, the fastener is applied by first approximating tissue portions in generaly face-to-face relationship. The hollow needles are inserted through the approximated tissue portions to locate the receiving openings on one side of the wound or incision and to locate at least portions of the discharge openings on the other side of the wound or incision. The fastening member is placed with each of the legs disposed in one of the needle passages and with the link extending through the needle slots between the needles. The fastening member is urged along the needles to locate at least a portion of the link on one side of the incision adjacent to one of the tissue portions and locate a portion of each leg on the other side of the incision where it is restrained by a suitable receiver. The needles are withdrawn and the fastener remains holding the tissue together.
Although many of the above discussed types of tissue fastening devices and techniques are satisfactory in various applications, there is a need to provide an improved method for fastening mammalian tissue with reduced trauma. It would also be desirable to provide an improved fastening method for use with fasteners fabricated from absorbable materials that can provide primary approximation of the tissue edges to insure that the tissue edges will not lose contact. The improved method should insure that the staple legs, as they pass through the tissue, fully align with the openings in the receiver. The improved method should eliminate the possibility of misalignment of the staple legs with the openings in the receiver. When misalignment occurs, blind movement of the legs is required until an opening is met, very often causing undue trauma to the tissue. The method of the present invention accomplishes all the above desired objectives.
Furthermore, many of the biocompatible materials which are most suitable for use within the human body lack the necessary physical characteristics to allow the material to be used as a fastening device. Often these materials do not have the required physical properties to allow them to be molded or otherwise manufactured into a staple with legs sufficiently strong and/or rigid that the legs have enough strength to penetrate tissue without breaking or bending. It is a further object of the present invention to provide a method that can be used with staples made from virtually any biocompatible polymeric materials even those materials having minimum strength and/or rigidity.
When using a staple having two or more staple legs joined together at one end of the legs and trying to push the staple through tissue so the free ends of the staple legs will meet openings in a receiver and be interlocked therewith, very often the staple legs will either converge or diverge as a result of the compressive force placed on them as the staple is being pushed through the receiver causing the staple legs to misalign with the openings in the receiver. This phenomenon results in non-fastening of the staple with the receiver or causes undue trauma to the tissue, both highly undesirable results. The method of the present invention eliminates this problem.
Also, it would be desirable to provide a relatively simple yet effective and rapidly operating instrument for applying a variety of fasteners according to such an improved method.